The flat glass which features high annealing point, environmental protection, energy saving, emission reduction, high strength, high evenness and low viscosity for modern flat buildings and industrial purpose manufactured by adopting float process, horizontal drawing process, Glaverbel process, calendaring process or overflow process, such as (1) door, window and wall glass for buildings, (2) glass for automobile and ship, (3) glass for high-speed rail, (4) LCD glass, (5) PDP glass, (6) TFT glass and high-strength panel glass for smartphone and iPad and (7) craft glass, has significant defects in the formula of production process as well as a technical prejudice; it adopts Na2O or B2O3 to melt SiO2; in the process of conventional melting technology, there is a technical prejudice for eutectic compositions; it is limited to the inherent compositions of silicon, calcium and aluminum; the viscosity is still not high even though about 13% Na2O or 8-15% B2O3 is added; a great deal of Al2O3 is not suggested to be added to enhance the product strength and annealing point, because by this way will it make the products in the prior art fail to control the product quality and output at higher viscosity temperature; besides, its energy-saving effect and strength are rather poor; particularly, boron volatilizes greatly, which makes the production of all existing alkali-free boron glass cause serious environmental problems.
(1) The prior art for alkali-free boron glass is represented alkali-free LCD glass with patent No. US2002/0011080A; in the technical solution for compositions, its patent material proposes that the content of SiO2 is up to 40-70%; in this kind of boron glass and embodiment, silicon occupies between 60-70% while the content of B2O3 is 5-20%; in actual use, the content of B2O3 in the product is up to 8%-15%, which aims to replace Na2O by B2O3 and achieve the purpose of fluxing; if the boron content is over 8%, 2-3 times of raw materials must be added; if the boron content is 10%, the raw material of 25-30% B2O3 content must be added (because most of them will become toxic gases and volatilize at a high temperature); its first technical defect lies in that its silicon content is too high, and the silicon is not easily melted; its second technical defect lies in that it will cause serious environmental damage; its third technical defect lies in that the molten pool will be severely corroded in actual production when the boron content is up to 5-20%; (therefore, all TFT LCD will be conducted with cold repair when high-boron glass molten pool is used only in one year; this will cause serious problems such as work efficiency and cost; the boron content is too high particularly when boron glass for flat LCD is manufactured; with the same content of Al2O3, it will lower the strength by one time; all existing LCD glass can only be manufactured by overflow due to its high boron content; its output is only 6-10 tons/day, which is equal to 5% or less output by float process (e.g.: minimally 150 tons/day); moreover, there is only one overflow production line with 6-10 tons/day; its equipment cost is 2-3 times that of the float line with 150 tons/day; therefore, it has become an industrial difficulty that is expected to be solved as to how to reduce the cost and improve the efficiency in the production of liquid crystal glass, conduct cold repair every 10 years like the common float glasswork and achieve viscosity reduction and energy saving.
(2) The existing soda-lime flat glass which features high annealing point, environmental protection, energy saving, emission reduction, high strength, high evenness and low viscosity includes [1] door, window and wall glass for buildings, [2] glass for automobile and ship, [3] glass for high-speed rail, [4] PDP glass and [5] craft glass; due to limited acknowledgement for its melt compositions, the viscosity temperature is higher than that of the present invention (150° C.-200° C.) in the process of melting and bubble discharge and homogenization; the energy is greatly consumed during production; every kilogram of the melt consumes 1,500 kilocalorie or higher.
(3) In the application of glass for automobile and high-speed rail, the existing industrial glass products do not have too high flexural strength and impact resistance; if the strength of automobile glass is poor, its safety is not guaranteed well; the ship glass is usually destroyed by sea waves; in particular, there is still a big gap in the requirements of impact resistance of automobile glass.
(4) As the flexural strength of existing industrial glass products is low (normally about or less than 50 MPa), and its impact resistance is much poorer; therefore, the glass in the front of airplane and in the left and right windows needs to be thickened; this will increase the weight and affect the dead weight of airplane and sight sharpness.
(5) In architectural application, its use scope is also greatly limited due to the low annealing point and the limit of strength performance of existing glass product; it is necessary to make it light, thin, high-strength and energy-saving.
(6) In the prior art, fireproof glass, hot plate glass, oven glass, microwave oven glass, panel glass for kitchen or dining table and existing soda-lime glass do not have such excellent linear characteristics with even ascending and descending in terms of expansion rate; its viscoelasticity changes a lot; cracking happens easily; therefore, it has some defects in this application.
(7) In addition, there is “crystallized glass having natural-marble-like surface patterns and method of producing the same” with a publication number CN1053047A; its process rather than the product compositions has determined its inevitable product defects.
1. Its process is stated as: collect the small frit in molding case, have . . . crystal entered from the glass surface into the internal part; the frits are melted and mixed; control the frit size . . . , obtain the appearances of marble and granite patterns; in this document, a lot of statements are about crystallization process, so it can be seen that it adopts a neoceramic glass process with color patterns for granule viscous-melt crystallization.
Its color patterns and non-transparency is obviously not determined by material compositions; the product's crystal, colors and patterns are determined by adding every glass granule from its surface to the internal part with the process method stated in the application document; therefore, every granule is filled with crystals from outside to inside; it is not transparent, so it is impossible to make such a product which has good visible light transmittance of 65%-95%; theses defects need to be overcome.